The object of this invention relates to an improvement in instructional and testing apparatus noted in the prior art. In recent years computers and related hardware and software have become much less expensive so that now home computers are commonplace. The present invention provides a way that these less expensive computers can be utilized in the instructional process as much of the information that would noramlly be stored in the computers memory can be presented in a variety of printed formats. In addition, the same preprinted instructional sheets that are in current use on a simple, nonelectronic teaching machine can also be used on a properly designed and manufactured teaching machine of the type described in this patent application. By the use of the simpler non-electronic teaching machine in conjunction with a more expensive computer linked teaching machine, this combination would provide a considerable cost savings for the regular classroom. With the use of this combination, a student could use the less expensive teaching machine for routine practice and drill, and the teacher could then select some of the instructional sheets for the student to respond to on the computer linked teaching machine in place of giving the student a standard test which the teacher has to grade. The students responses on those instructional sheets that are selected by the teacher as the test would then be stored in the computers memory and printed out for the teacher on command of the teacher. This would also result in a saving of the teacher's time, as less time would be spent in grading tests. The computer could also be programmed to do a number of different analytic processes on the data placed in it's memory, or stored on tapes or discs. When used by the student in a classroom, this teaching machine and testing apparatus could be used in either the immediate feedback (teaching) mode, or in the no immediate feedback (testing) mode.
Part of the background of this invention has to do with the construction and production of electrical resistance material in sheet or film form. The most common type of electrical resistors are those constructed in rod or bar form with wires extending from each end. Other types of resistors are constructed to have different degrees of electrical resistance. Resistors can be constructed from coils of resistive wire and taps are placed at intervals along such a resistive coil to give a number of different resistances from the same coil. Variable resistors such as are used in the volume control of a radio are often constructed from a band of resistive material that has been formed into an incomplete ring. And located at the central axis of this ring is a conductive shaft with an attached conductive arm that sweeps around the inside of this ring as the shaft is rotated, thus providing a great degree of variation in electrical resistance from one position to another. Elastic sheets or films of resistive material are produced by mixing elastic polymers with electrically resistive materials in different ratios. The amount of electrical resistance per unit of distance on the sheet can varied by (1.) useing different resistive materials; (2.) useing different ratios of nonconductive elastic polymers and a given resistive material; and (3.) by extruding the resistive films or sheets in different thicknesses. When a rectangular sheet of resistive material has a highly conductive strip attached along one edge, then the resistance value of any point on that sheet (providing it is of uniform construction and thickness) to this conductive strip is directly related to the distance between the point and the conductive strip. When this conductive strip is attached in a straight line along one edge of the resistive sheet, then all points of equal distance from this strip will have the same resistance values, and these points will also fall in a straight line. With this arrangement, if row of points "B" is one half the distance to the edge of the conductive strip as compared to row of points "C", then the electrical resistance along row of points "B" will be one half the value of row of points "C" when the resistance is measured between these two rows of points and the conductive strip. In a like manner, if row of points "D" on this resistive sheet is three times the distance from the conductive strip as row of points "B", then the electrical resistances along line of points "D" will be three times as great as the electrical resistance along row of points "B".
One of the objects of this invention is to utilize the different electrical resistance values that can be obtained in the manner described above to define the X and Y coordinates of a grid pattern. The X and Y coordinates of this grid pattern have points of intersection that correspond to the grid pattern used as answer areas on instructional sheets that are place over two electroresistive sheets. Said electroresistive sheets are place one above the other, but normally are only in contact with each other when downward pressure is exerted at an answer area on an overlying instructional sheet. The different resistance values obtained from downward pressure on points at different locations on this grid are used in conjunction with a computer to give students feedback as to their correct and incorrect responses, and this information is also stored in the computers memory for later further evaluation.